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Manufacturing and Investigating of Polypropylene/Silica Nanocomposites via in-situ Polymerization and Using Bi-supported Ziegler-Natta Catalyst

Azinfar, Bahareh | 2011

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 42319 (06)
  4. University: Sharif University of Technology
  5. Department: Chemical and Petroleum Engineering
  6. Advisor(s): Ramezani Saadat, Ahmad
  7. Abstract:
  8. The main object of this thesis is production and investigation of polypropylene-fumed silica nanocomposites by using bi-supported Ziegler-natta catalytic system and in-situ polymerization. Magnesium ethoxide and fumed silica were used as supports of catalyst. TiCl4 was accompanied by triisobutyl aluminum(TiBA) and diisobutyl phthalate(DIBP) as electron doner constituting Ziegler-Natta catalytic system. Preparation of catalyst and polymerization were taken place in slurry phase under the argon atmosphere. At the beginning of the polymerization experiment, several type of nanocomposites were made under various conditions(such as different Al/Ti molar ratio) to find optimum condition to achieve maximum polymerization yield. Then, structural, thermal and rheological properties of produced nanocomposites with different fumed silica content were evaluated by MFI, SEM, DSC, TGA, dynamic and steady rheological tests. MFI test results show that melt flow index decreases with addition of fumed silica. Also the gel content of samples were determined by soxhelt extraction and it was found that the present of gel decreased processability of nanocomposites. Scanning Electron Microscopy (SEM) images shows good dispersion for fumed silica throughout PP matrix. Crystallization behavior was tested by using Differential Scanning Calorimetry (DSC). Results show that crystal content increases significantly with addition of fumed silica. The same results observed for melting and crystallization temperatures. Thermogravimetric analysis (TGA) shows thermal stability improvement with fumed silica addition. The effect of filler on storage and loss modulus and complex viscosity were studied by dynamic rheological tests. Storage and loss modulus and complex viscosity increase by introducing fumed silica. Also, the steady shear tests show highly shear thinning behavior of nanocomposites
  9. Keywords:
  10. Fumed Silica ; Ziegler-Natta Catalyst ; In-situ Polymerization ; Support ; Polypropylene Nanocomposite

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